Silesauridae is an exclusively Triassic group of dinosauromorphs, knowledge on the diversity of which has increased dramatically in the last few years. Silesaurid relationships are still contentious, as a result in part of different homology statements, particularly regarding the typical edentulous mandible tip of these animals. One of the most complete silesaurids yet discovered is Sacisaurus agudoensis from the Caturrita Formation (Late Triassic: Norian) of Rio Grande do Sul, Brazil, represented by numerous isolated bones recovered from a single site. The anatomy of S. agudoensis is fully described for the first time here, and comparisons are provided to other basal dinosauromorphs. S. agudoensis is a small-bodied animal (less than 1 m in length) that possesses a dentition consisting of leaf-shaped crowns with large denticles in the carinae, a plesiomorphic propubic pelvis with an almost fully closed acetabulum, elongate distal hindlimbs suggesting well-developed cursorial ability, and a laterally projected outer malleolus in the tibia. All previous numerical phylogenies supported a non-dinosaur dinosauromorph affinity for Silesauridae, but the reanalysis of one of those studies suggests that a position within Dinosauria is not unlikely, with silesaurids forming the basal branch of the ornithischian lineage.

a. Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, United Kingdom; and

b. Large Lakes Observatory and Department of Geological Sciences, University of Minnesota, Duluth, MN 55812Abstract:

The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time.

If they team with the Americans, they will develop a plane with a planform like that on the lext. If they team with the Europeans, they will work on a planform on the right. To my eyes, the one on the left looks like a muscled up JSF. The one on the right looks like a stealthy Draken.

Monday, April 29, 2013

Many scientists have thought that dinosaur predecessors missed the race to fill habitats emptied when nine out of 10 species disappeared during the Earth's largest mass extinction, approximately 252 million years ago. The thinking was based on fossil records from sites in South Africa and southwest Russia.

It turns out that scientists may have been looking for the starting line in the wrong places.

Newly discovered fossils from 10 million years after the mass extinction reveal a lineage of animals thought to have led to dinosaurs taking hold in Tanzania and Zambia in the mid-Triassic period, many millions of years before dinosaur relatives were seen in the fossil record elsewhere on Earth.

"The fossil record from the Karoo of South Africa remains a good representation of four-legged land animals across southern Pangea before the extinction event. But after the event animals weren't as uniformly and widely distributed as before. We had to go looking in some fairly unorthodox places," said Christian Sidor, University of Washington professor of biology. He's lead author of a paper appearing the week of April 29 in the early edition of the Proceedings of the National Academy of Sciences.

The new insights come from seven fossil-hunting expeditions since 2003 in Tanzania, Zambia and Antarctica, funded by the National Geographic Society and National Science Foundation, along with work combing through existing fossil collections. The researchers created two "snapshots" of four legged-animals about 5 million years before and again about 10 million years after the extinction event at the end of the Permian period.

Prior to the extinction event, for example, the pig-sized Dicynodon – said to resemble a fat lizard with a short tail and turtle's head – was a dominant plant-eating species across southern Pangea. Pangea is the name given to the landmass when all the world's continents were joined together. Southern Pangea was made up of what is today Africa, South America, Antarctica, Australia and India. After the mass extinction at the end of the Permian, Dicynodon disappeared and other related species were so greatly decreased that newly emerging herbivores could suddenly compete with them.

"Groups that did well before the extinction didn't necessarily do well afterward," Sidor said. "What we call evolutionary incumbency was fundamentally reset."

The snapshot 10 million years after the extinction event reveals, among other things, that archosaurs were in Tanzanian and Zambian basins, but not distributed across all of southern Pangea as had been the pattern for four-legged animals prior to the extinction. Archosaurs are the group of reptiles that includes crocodiles, dinosaurs, birds and a variety of extinct forms. They are of interest because it is thought they led to animals like Asilisaurus, a dinosaur-like animal, and Nyasasaurus parringtoni, a dog-sized creature with a five-foot tail that scientists in December 2012 announced could be the earliest dinosaur, or else the closest relative found so far.

The discovery of an extremely well preserved new juvenile specimen of Sapeornis provides more anatomical information about this basal avian, and documents the first avian specimen from the Jehol Biota with detailed foot-pad integument preserved. This is the first Sapeornis specimen with a well preserved carpal X, astragalus and calcaneum. Seven major skeletal components from five well preserved juvenile and adult skeletons of Sapeornis were measured. The allometric differences associated with growth are shown to be distinct; all linear regressions resulted in high correlation coefficients consistent with a single growth series. The number of sacral vertebrae and free caudal vertebrae vary during ontogeny, and this may indicate that all the specimens can be assigned to a single species: Sapeornis chaoyangensis.

Dashed lines are approximate boundaries of the extent of settlement based on dated archaeological sites, and solid arrows are hypothesized population movements. A) The initial expansion into southern Siberia from central Asia is relatively uncontroversial. B) Similarly, the expansion from southern Siberia to far-western Beringia by ~30k calBP is uncontroversial. C) Three proposed pre-LGM colonization routes include coastal, terrestrial, and trans-Arctic routes, however, currently there are no archaeological sites beyond western Beringia to support these routes. D) Post-LGM models include the traditional trans-Beringian route, and a coastal route. The trans-Beringian route is the best supported by current archaeological data, and there is no archaeological evidence to suggest the coastal route was a major factor in colonization, albeit complicated by Holocene sea level rise along the Pacific Rim. However, it is entirely feasible that as colonists expanded across the Beringian mainland local groups close to the southern coast may have included aquatic resources in the diet. However, there is no evidence of full maritime cultures anywhere along the Pacific Rim until well into the Holocene.

e. Department of Anthropology, University of Missouri, Columbia, Missouri, United States of America

Abstract:

Understanding the dynamics of the human range expansion across northeastern Eurasia during the late Pleistocene is central to establishing empirical temporal constraints on the colonization of the Americas [1]. Opinions vary widely on how and when the Americas were colonized, with advocates supporting either a pre- or post- last glacial maximum (LGM) colonization, via either a land bridge across Beringia, a sea-faring Pacific Rim coastal route, a trans-Arctic route, or a trans-Atlantic oceanic route. Here we analyze a large sample of radiocarbon dates from the northeast Eurasian Upper Paleolithic to identify the origin of this expansion, and estimate the velocity of colonization wave as it moved across northern Eurasia and into the Americas.

The lines represent the closest path for connecting all samples according to the morphological distances between them. Red dots represent samples with Paleoamerican morphology and the brown dot represents the specimens from Zhoukoudian Upper Cave. Blue dots indicate the Late Holocene samples from East Asia, the Americas and Australo-Melanesia.

Discussion surrounding the settlement of the New World has recently gained momentum with advances in molecular biology, archaeology and bioanthropology. Recent evidence from these diverse fields is found to support different colonization scenarios. The currently available genetic evidence suggests a “single migration” model, in which both early and later Native American groups derive from one expansion event into the continent. In contrast, the pronounced anatomical differences between early and late Native American populations have led others to propose more complex scenarios, involving separate colonization events of the New World and a distinct origin for these groups.

North America hosted a diverse assemblage of horned dinosaurs from the late Campanian until the end of the Cretaceous, but comparatively little is known about earlier horned dinosaurs. This paper reports on previously undescribed ceratopsian remains from the middle Campanian beds of the Judith River Formation of Montana, which represent the oldest known chasmosaurine. The Judith River chasmosaur shows a combination of characters not seen in any previously described ceratopsid. The parietal has a broad median bar, a rounded caudal margin, and highly reduced epiparietals. Episquamosals are enlarged anteriorly but decrease in size posteriorly, and imbricate as in centrosaurines. The postorbital horns are moderately elongate, inclined anterolaterally, and have an unusual teardrop-shaped cross section. The unique combination of characters seen in the Judith River chasmosaurine precludes referral to any previously known genus, and it is therefore described as a new genus and species, Judiceratops tigris. The addition of Judiceratops to the dinosaurian fauna of North America underscores the diversity of horned dinosaurs in the Late Cretaceous, which results from a combination of high diversity within faunas, a high degree of endemism, and rapid faunal turnover.

A billionaire-backed asteroid-mining company aims to start putting its big plans into action soon, launching its first hardware into space by this time next year.

Planetary Resources, which counts Google execs Larry Page and Eric Schmidt among its investors, plans to loft a set of tiny "cubesats" to Earth orbit in early 2014, to test out gear for its first line of asteroid-prospecting spacecraft.

"Our belief and our philosophy is that the best testbed is space itself," Chris Voorhees, Planetary Resources' vice president of spacecraft development, said Wednesday (April 24) during a Google+ Hangout event. [Planetary Resources' Asteroid-Mining Plans (Images)]

"Despite the fact that we're a deep-space company, we're going to use Earth orbit as much as possible," Voorhees added. "For us, it's a valuable learning experience, and that's what we plan on doing one year hence."

The cubesats slated for launch in 2014 will measure 12 inches long by 4 inches wide by 4 inches tall (30 by 10 by 10 centimeters), company officials said. These "Arkyd-3" satellites will test out technologies for Planetary Resources' Arkyd-100 scouts, which the firm hopes to launch to low-Earth orbit on asteroid-hunting missions in 2015.

The Arkyd-3 "is the testbed manifestation of our Arkyd-100 spacecraft. It just happens to be flying," Voorhees said.

Pterosaurs are a clade of highly specialized, volant archosauromorphs recorded from the Upper Triassic to the uppermost Cretaceous. Problematic remains referred to the Pterosauria are reported from the Triassic of Europe and both North and South America, but unequivocal pterosaur specimens are only known from the Alps (Italy, Austria and Switzerland: Preondactylus buffarinii, Austriadactylus cristatus, Peteinosaurus zambellii, Eudimorphodon ranzii, Carniadactylus rosenfeldi, Caviramus schesaplanensis and Raeticodactylus filisurensis) and Greenland (‘Eudimorphodon’ cromptonellus). Pterosaurs are diagnosed mostly by features associated with the advent of powered flight. They are generally considered to be archosaurians more closely related to dinosaurs than to crocodilians, but non-archosaurian positions have also been proposed. There is a lack of general agreement about ingroup relationships, particularly among the basal pterosaurs. Triassic pterosaurs differ from other non-pterodactyloid pterosaurs in features of the dentition and caudal vertebral column. A ‘Big Bang’ model for their early history fits better with the fossil record: the earliest unequivocal pterosaurs show a sudden and geographically limited appearance in the fossil record, as well as a relatively high burst of diversity and considerable morphologic disparity. Absence of pterosaur remains from deposits where they are expected to be found suggests that they had not yet evolved in pre-Norian times.

The well-known Maastrichtian-Ypresian vertebrate-bearing phosphate series, in the Ouled Abdoun Basin, Morocco, is classically dated using regional selachian biostratigraphic zonation. These marine sediments yielded Paleocene and Eocene mammals comprising the earliest known placentals from Africa. This study provides the first insight into the organic carbon isotope chemostratigraphy (δ13Corg) of the Moroccan phosphate series and a refined dating of its vertebrate-bearing levels. Four Paleocene-Eocene sections in the NE Ouled Abdoun quarries show consistent δ13Corg long term evolutions, from the base to the top: 1) positive trend in phosphorite Bed IIa, beginning with the lower Bone Bed yielding mammals such as Eritherium, Ocepeia, Abdounodus, Lahimia, of early Thanetian and Selandian age; 2) transitional negative trend in the Intercalary phosphorite Beds II/I that includes the Otodus obliquus and Phosphatherium escuilliei Bone Bed of earliest Ypresian age; 3) negative trend to the lowermost δ13Corg values that are correlative to the early-middle Ypresian interval including ETM 2 and ETM 3 hyperthermal events in the global record; 4) positive trend in chert-enriched facies containing the middle Ypresian EECO global climatic event. Our chemostratigraphic study of the Ouled Abdoun phosphate series provides a new chronostratigraphic framework for calibrating the beginning of the evolution of placental mammals in Africa. The lower Bone Bed level from the Paleocene phosphorite Bed IIa yielding Eritherium is not younger than early Thanetian, and is most likely Selandian. The Phosphatherium Bone Bed in the Intercalary Beds II/I is earliest Ypresian. The phosphorite Bed 0, from which Daouitherium probably came, is early-middle Ypresian, just below the EECO. This suggests that the first large proboscideans evolved after the PETM, during mid-Ypresian warming events. The δ13Corg study does not support the presence of Lutetian in the NE Ouled Abdoun phosphate series and suggests that a noticeable part of the upper Thanetian is absent.

Thursday, April 25, 2013

The Maya civilization is well-known for its elaborate temples, sophisticated writing system, and mathematical and astronomical developments, yet the civilization's origins remain something of a mystery.

A new University of Arizona study to be published in the journal Science challenges the two prevailing theories on how the ancient civilization began, suggesting its origins are more complex than previously thought.

Anthropologists typically fall into one of two competing camps with regard to the origins of Maya civilization. The first camp believes that it developed almost entirely on its own in the jungles of what is now Guatemala and southern Mexico. The second believes that the Maya civilization developed as the result of direct influences from the older Olmec civilization and its center of La Venta.

It's likely that neither of those theories tells the full story, according to findings by a team of archaeologists led by UA husband-and-wife anthropologists Takeshi Inomata and Daniela Triadan.

"We really focused on the beginning of this civilization and how this remarkable civilization developed," said Inomata, UA professor of anthropology and the study's lead author.

In their excavations at Ceibal, an ancient Maya site in Guatemala, researchers found that Ceibal actually predates the growth of La Venta as a major center by as much as 200 years, suggesting that La Venta could not have been the prevailing influence over early Mayan development.

That does not make the Maya civilization older than the Olmec civilization – since Olmec had another center prior to La Venta – nor does it prove that the Maya civilization developed entirely independently, researchers say.

What it does indicate, they say, is that both Ceibal and La Venta probably participated in a broader cultural shift taking place in the period between 1,150-800 B.C.

"We're saying that the scenario of early Maya culture is really more complex than we thought," said UA anthropology graduate student Victor Castillo, who co-authored the paper with Inomata and Triadan.

"We have this idea of the origin of Maya civilization as an indigenous development, and we have this other idea that it was an external influence that triggered the social complexity of Maya civilization. We're now thinking it's not actually black and white," Castillo said.

There is no denying the striking similarities between Ceibal and La Venta, such as evidence of similar ritual practices and the presence of similar architecture – namely the pyramids that would come to be the hallmark of Mesoamerican civilization but did not exist at the earlier Olmec center of San Lorenzo.

However, researchers don't think this is the case of simply one site mimicking the other. Rather, they suspect that both the Maya site of Ceibal and the Olmec site of La Venta were parts of a more geographically far-reaching cultural shift that occurred around 1,000 B.C., about the time when the Olmec center was transitioning from San Lorenzo to La Venta.

"Basically, there was a major social change happening from the southern Maya lowlands to possibly the coast of Chiapas and the southern Gulf Coast, and this site of Ceibal was a part of that broader social change," Inomata said. "The emergence of a new form of society – with new architecture, with new rituals – became really the important basis for all later Mesoamerican civilizations.

Alignment:Neutral Good A neutral good character does the best that a good person can do. He is devoted to helping others. He works with kings and magistrates but does not feel beholden to them. Neutral good is the best alignment you can be because it means doing what is good without bias for or against order. However, neutral good can be a dangerous alignment when it advances mediocrity by limiting the actions of the truly capable.

Race:Humans are the most adaptable of the common races. Short generations and a penchant for migration and conquest have made them physically diverse as well. Humans are often unorthodox in their dress, sporting unusual hairstyles, fanciful clothes, tattoos, and the like.

Class:Wizards are arcane spellcasters who depend on intensive study to create their magic. To wizards, magic is not a talent but a difficult, rewarding art. When they are prepared for battle, wizards can use their spells to devastating effect. When caught by surprise, they are vulnerable. The wizard's strength is her spells, everything else is secondary. She learns new spells as she experiments and grows in experience, and she can also learn them from other wizards. In addition, over time a wizard learns to manipulate her spells so they go farther, work better, or are improved in some other way. A wizard can call a familiar- a small, magical, animal companion that serves her. With a high Intelligence, wizards are capable of casting very high levels of spells.

Numerous studies along the northern Mediterranean borderland have documented the use of shellfish by Neanderthals but none of these finds are prior to Marine Isotopic Stage 3 (MIS 3). In this paper we present evidence that gathering and consumption of mollusks can now be traced back to the lowest level of the archaeological sequence at Bajondillo Cave (Málaga, Spain), dated during the MIS 6. The paper describes the taxonomical and taphonomical features of the mollusk assemblages from this level Bj19 and briefly touches upon those retrieved in levels Bj18 (MIS 5) and Bj17 (MIS 4), evidencing a continuity of the shellfishing activity that reaches to MIS 3. This evidence is substantiated on 29 datings through radiocarbon, thermoluminescence and U series methods. Obtained dates and paleoenvironmental records from the cave include isotopic, pollen, lithostratigraphic and sedimentological analyses and they are fully coherent with paleoclimate conditions expected for the different stages. We conclude that described use of shellfish resources by Neanderthals (H. neanderthalensis) in Southern Spain started ~150 ka and were almost contemporaneous to Pinnacle Point (South Africa), when shellfishing is first documented in archaic modern humans.

A research team of biogeochemists at the University of California, Riverside has provided a new view on the relationship between the earliest accumulation of oxygen in the atmosphere, arguably the most important biological event in Earth history, and its relationship to the sulfur cycle.

A general consensus exists that appreciable oxygen first accumulated in Earth's atmosphere around 2.4 to 2.3 billion years ago. Though this paradigm is built upon a wide range of geological and geochemical observations, the famous "smoking gun" for what has come to be known as the "Great Oxidation Event" (GOE) comes from the disappearance of anomalous fractionations in rare sulfur isotopes.

"These isotope fractionations, often referred to as 'mass-independent fractionations,' or 'MIF' signals, require both the destruction of sulfur dioxide by ultraviolet energy from the sun in an atmosphere without ozone and very low atmospheric oxygen levels in order to be transported and deposited in marine sediments," said Christopher T. Reinhard, the lead author of the research paper and a former UC Riverside graduate student. "As a result, their presence in ancient rocks is interpreted to reflect vanishingly low atmospheric oxygen levels continuously for the first ~2 billion years of Earth's history."

However, diverse types of data are emerging that point to the presence of atmospheric oxygen, and, by inference, the early emergence of oxygenic photosynthesis hundreds of millions of years before these MIF signals disappear from the rock record. These observations motivated Reinhard and colleagues to explore the possible conditions under which inherited MIF signatures may have persisted in the rock record long after oxygen accumulated in the atmosphere.

Using a simple quantitative model describing how sulfur and its isotopes cycle through the Earth's crust, the researchers discovered that under certain conditions these MIF signatures can persist within the ocean and marine sediments long after O2 increases in the atmosphere. Simply put, the weathering of rocks on the continents can transfer the MIF signal to the oceans and their sediments long after production of this fingerprint has ceased in an oxygenated atmosphere.

"This lag would blur our ability to date the timing of the GOE and would allow for dynamic rising and falling oxygen levels during a protracted transition from an atmosphere without oxygen to one rich in this life-giving gas," Reinhard said.

The Jurassic–Cretaceous (J–K) boundary is one of the most problematic points on the geological timescale. The boundary is not defined by a Global Stratotype Section and Point (GSSP) because of the absence of well-defined (by significant faunal turnover), widely correlatable biostratigraphic levels to fix the base of the Berriasian. A distinct earliest Berriasian positive carbon isotope excursion is identified in the Boreal marine carbonate (belemnites) carbon records from the Maurynya River (Northern Urals) and the Nordvik Peninsula (northern East Siberia). The excursion is found within the top part of the upper Volgian Craspedites taimyrensis ammonite Zone, slightly above the J–K boundary, which was established by palaeomagnetic data. Because a significant positive δ13C shift was also observed immediately above the J–K boundary in the Tethyan Guppen-Heuberge pelagic-carbonate section (Switzerland), this positive carbon isotope event can be regarded as a useful marker for a Panboreal and Boreal–Tethyan correlation of J–K boundary beds. This δ13C excursion is interpreted as a record of increased rates of organic carbon burial. The δ13C data obtained previously for the upper Volgian and Ryazanian in different Boreal regions are also analysed in this paper. Other well-documented carbon isotope excursions with less global significance allow the creation of a composite carbon-isotope curve for Boreal regions that characterises the upper Volgian and Ryazanian in detail.

Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth's crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie's Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in Nature.

Oceanic crust sinks into the Earth's mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth's surface via upwellings of magma has not been found until now.

The research team studied volcanic rocks from the island of Mangaia in Polynesia's Cook Islands that contain iron sulfide inclusions within crystals. In-depth analysis of the chemical makeup of these samples yielded interesting results.

The research focused on isotopes of the element sulfur. (Isotopes are atoms of the same element with different numbers of neutrons.) The measurements, conducted by graduate student Rita Cabral, looked at three of the four naturally occurring isotopes of sulfur--isotopic masses 32, 33, and 34. The sulfur-33 isotopes showed evidence of a chemical interaction with UV radiation that stopped occurring in Earth's atmosphere about 2.45 billion years ago. It stopped after the Great Oxidation Event, a point in time when the Earth's atmospheric oxygen levels skyrocketed as a consequence of oxygen-producing photosynthetic microbes. Prior to the Great Oxidation Event, the atmosphere lacked ozone. But once ozone was introduced, it started to absorb UV and shut down the process.

This indicates that the sulfur comes from a deep mantle reservoir containing crustal material subducted before the Great Oxidation Event and preserved for over half the age of the Earth.

"These measurements place the first firm age estimates of recycled material in oceanic hotspots," Hauri said. "They confirm the cycling of sulfur from the atmosphere and oceans into mantle and ultimately back to the surface," Hauri said.

China will build a second, larger aircraft carrier capable of carrying more fighter jets, the official Xinhua news service reported late Tuesday, quoting a senior officer with the People's Liberation Army (PLA) Navy.

The report comes after Chinese officials denied foreign media reports in September 2012 that China was building a second carrier in Shanghai.

"China will have more than one aircraft carrier ... The next aircraft carrier we need will be larger and carry more fighters," Xinhua quoted Song Xue, deputy chief of staff of the PLA Navy, as saying at a ceremony with foreign military attaches.

Song said foreign media reports saying the carrier was being built in Shanghai were still inaccurate but did not elaborate, according to the report.

China currently has one aircraft carrier, the Liaoning, which was refitted from a Russian-made model. Considered by military experts to be decades behind U.S. carrier technology, it was originally intended to serve as a floating casino, but was turned to military use in the runup to a once-in-a-decade power transition in late 2012.

China is also building up other forms of military hardware, including a stealth fighter jet believed to be capable of landing on a carrier, drone aircraft and nuclear submarines.

"In 2013 we are expected to wrap up its preliminary tests and start operational testing. In 2014, we are planning to start official state tests," says United Aircraft Corporation president Mikhail Pogosyan. The first stage of those state trials should be completed by 2015.

The PAK-FA developmental flight test phase includes six airframes, but one is a ground test vehicle. "Flight testing this year will go ahead with five aircraft," Pogosyan says.

I hope they ahve changed their manufacturing. Rivets are bad for stealth, m'kay.

Tuesday, April 23, 2013

DNA recovered from ancient skeletons reveals that the genetic makeup of modern Europe was established around 4,500 years ago in the mid-Neolithic, and not by the first farmers who arrived in the area around 7,500 years ago or by earlier hunter-gatherer groups. (Read about Europe's oldest known town.)

"The genetics show that something around that point caused the genetic signatures of previous populations to disappear," said Alan Cooper, director of the Australian Centre for Ancient DNA at the University of Adelaide, where the research was performed.

"However, we don't know what happened or why, and [the mid-Neolithic] has not been previously identified as [a time] of major change," he said.

Furthermore, the origins of the mid-Neolithic populations that did form the basis of modern Europe are also unknown.

"This population moves in around 4,000 to 5,000 years ago, but where it came from remains a mystery, as we can't see anything like it in the areas surrounding Europe," Cooper said.

The surprising findings are part of a new study, published in this week's issue of the journal Nature Communications, that provides the first detailed genetic history of modern Europe.

The most comprehensive evaluation of temperature change on Earth's continents over the past 1,000 to 2,000 years indicates that a long-term cooling trend--caused by factors including fluctuations in the amount and distribution of heat from the sun, and increases in volcanic activity--ended late in the 19th century.

The study also finds that the 20th century ranks as the warmest or nearly the warmest century on all of the continents, except Antarctica. Africa had insufficient data to be included in the analysis.

Global warming that has occurred since the end of the 19th century reversed a persistent long-term global cooling trend, say the researchers.

A consortium of 78 authors from 24 countries, some of them supported by the National Science Foundation (NSF), also note in research published in the May 2013 issue of the journal Nature Geoscience that there were regional differences in temperature evolution.

"This is an example of a large international team effort, collaborating to synthesize new scientific results from a very large, publicly available dataset," said Paul E. Filmer, program director for the Paleoclimate, Sedimentary Geology and Paleobiology and ArcSEES programs in NSF's Geosciences Directorate.

The researchers are members of the "2K Network" of the International Geosphere Biosphere Program (IGBP) Past Global Changes (PAGES) project. The Swiss National Science Foundation and the US NSF jointly support the PAGES International Project Office.

"Global warming that has occurred since the end of the 19th century reversed a persistent long-term global cooling trend," the researchers write in the report.

Because long-range cooling was caused by natural factors that continued to exist in the 20th century, the authors argue, the warming of the 20th century makes it more difficult to discount the effects of the increase of greenhouse gases in the global increase of temperatures measured in recent decades.

Its more like a manufacturing unit than a autonomous robot. However,if the company would add a machine to load the ingredients and combine it with the cutter unit they already have, you'd be all set. Consider it a generation away then.

The beginning of dinosaur evolution is currently known based on a handful of upper Carnian–lowermost Norian (232–225 Mya) localities situated in a paleolatitudinal belt of approximately 40–50° S in Argentina, Brazil, Zimbabwe and India. The taxonomic diversity of the oldest known dinosaurbearing assemblages, included within the Hyperodapedon Assemblage Zone, is reviewed here. The Brazilian “Teyuwasu barberenarai” is reinterpreted as a nomen dubium representing an indeterminate dinosauriform, the record of cf. Saturnalia from Zimbabwe is considered a basal saurischian and only one of the Indian specimens described by Huene can be unambiguously assigned to Dinosauria. The highest early dinosaur species richness sampled is concentrated in southwestern Pangean assemblages (Argentina and Brazil), with 10 to 11 different described species. By contrast, only one or two species can be currently recognized from the approximately coeval beds of south–central Pangea (Zimbabwe and India), which are much less well sampled. The oldest known dinosaur assemblages appear to have been mostly restricted to subtropical to cool temperate arid areas based on recent paleoclimatological reconstructions. This observation agrees with the hypothesis that the absence of dinosaurs in the upper levels of the Ischigualasto Formation of Argentina is related to an increase in humidity in the basin. Accordingly, climatic factors, with humidity as probably the most important, may have controlled the paleobiogeographic distribution of the oldest known dinosaur assemblages. The achievement of a worldwide dinosaur distribution during the latest Triassic may have occurred after a global climate change, such as the end of the “Carnian Pluvial Event”, and/or the invasion of more tropical humid climates by dinosaurs.

One of the major elements of Afghanistan’s air war will remain after most U.S. troops have headed home, the U.S. military command confirmed today. Armed drones, operated by the U.S., will remain over Afghanistan after 2014.

The largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents. Previous reports of gut contents and considerations of functional morphology have indicated that Microraptor hunted in an arboreal environment. The new specimen demonstrates that this was not strictly the case, and offers unique insights into the ecology of nonavian dinosaurs early in the evolution of flight. The preserved gut contents are composed of teleost fish remains. Several morphological adaptations of Microraptor are identified as consistent with a partially piscivorous diet, including dentition with reduced serrations and forward projecting teeth on the anterior of the dentary. The feeding habits of Microraptor can now be understood better than that of any other carnivorous nonavian dinosaur, and Microraptor appears to have been an opportunistic and generalist feeder, able to exploit the most common prey in both the arboreal and aquatic microhabitats of the Early Cretaceous Jehol ecosystem.

The rich assemblage of continental vertebrates from the Cenomanian Kem Kem Beds (Morocco) is one of the best known and most diversified for the mid Cretaceous period (Cenomanian). This assemblage, however, shows apparent ecological oddities, in particular the overabundance of theropod dinosaurs versus plant-eating dinosaurs. Several hypotheses have been proposed to explain this unbalanced ratio, including a peculiar ecosystem, non-systematic collecting, taphonomic factors, stratigraphic uncertainties and/or behavioral aspects of the dinosaur groups concerned. Except the comparison of proportions of taxa between field and shop data (McGowan and Dyke, 2009), the other hypotheses have not been tested so far because of the lack of accurately measured sections and systematically collected field data. Based on new field data, we test the above-mentioned hypotheses. The analysis is focused on the ratio of plant-eating versus carnivorous dinosaurs.

This dataset confirms the unbalanced ratio; moreover, the stratigraphic distribution of fossils is quantitatively not homogeneous and consequently important to avoid time-averaging, i.e. the mixing of fossils of different ages together into a single unit. The origin of the unbalanced food web among dinosaurs is related neither to non-systematic collecting, nor to stratigraphic biases. The palaeoenvironment seems to be the only likely factor to explain the significantly high proportion of carnivorous versus plant-eating dinosaurs. Indeed, the deltaic palaeoenvironment offered unfavourable conditions for the setting of stable terrestrial vegetation but favoring aquatic life. This aquatic life formed the basic level of an aquatic or semi-aquatic food web, which directly fed top predators, such as theropods in general and spinosaurs in particular.

A friend of mine strongly recommended that I read the latest book in the Pournelle-verse. He actually did this a while ago, but I’ve not been reading much these days other than technical literature and what I can quickly read online. I’m too busy. I’d taken to writing to reduce stress, but while it works, there are days when I am too kaput to write and would like to enjoy someone else’s imaginary world. Given that I did the post 4000 on the Pournelle verse and Carlos said that Outies was a very good book. I thought that I ought to dive into that, like returning to an enjoyable restaurant that I used to visit for years. Except, now, the proprietor is the daughter of the owner I knew and there have been changes. For the most part, they are good ones.

Outies is set as a sequel to The Gripping Hand and The Mote in God’s Eye. It has a different flavour than those two works. The first was largely a POV from the aristocracy of the Empire of Man: Pournelle the Elder was probably the stronger voice in the setting and characters. The second was the POV of Bury, Renner and the kids of the aristocracy: Niven was a far stronger voice in this work and it had more akin to his works than the others in the Pournelleverse. Unfortunately, The Gripping Hand was an infuriating work. There was no Heinlein to write a novel length critique on it and it showed. A lot. Outies is a VERY different POV work and this is due to Jennifer Pournelle’s rather different experiences, as an officer and archaeologist in Iraq. Her POV characters are both academics and field personnel that are not exactly of the power structure. The glimpses of Rod Blaine et al are rather different than those in the first two books and there are realistic reasons for it and authorial ones.

Let me come out and say that despite the fact that Pournelle the Elder was one of those that helped found milsf as a genre, this book does not belong to that tradition. There are probably more commonalities with those that explore the great game between Britain and Russia on the frontier which have more in common with this work than milsf does. Likewise, if you are expecting lots of shiny $tech, this is not the place either: it makes a gracing at the end, but by and large its not important to the story. This story is about people. Be warned.

There is too much that is too important to the plot which would be far too easy to give away. The basic premise is that New Utah is being offered a place in the Empire of Man. It was offered one 21 years prior and it turned it down. Normally, this would be a disaster for a world, then being completely colonized by the Empire if it was a weak world like New Utah or being declared an Outie and all trade cut off. New Utah has an intermittent jump point and the Empire won’t be back in force for some time. When New Utah declines, they are declared Outies and trade cut off. However, the Empire is back and offering a chance again. This causes all sorts of hell to break loose. Ascension politics is something not exactly explored much before other than King David’s Spaceship. This is a very different take.

The world of New Utah was obviously deeply influenced by the author’s experiences in Iraq. While Muslims do have their place in the book, instead there is exploration of the factions between an extrapolated pair of religions: the Latter Day Saints and the Himmists. The latter you will recognize from the original book in the series. The former is more familiar. I normally approach authorial treatments of the LDS with dread: either they uber praise them or completely misconstrue the LDS. Caveat: I grew up Mormon, but have not been to church in a couple decades for my own reasons. However, Pournelle treats this with care. There are several LDS churches now and Dr Pournelle has written a nuanced view of them. Given this is over a millennium in the future, I can take misconstrued doctrine as acceptable. The Catholic Church of 1013 is not exactly the Catholic Church of 2013. I also liked that there were heroes and monsters and everything between, but for the most part, they were just plain human.

Of the characters, I rather liked the Librarian and Asach. I’ve known and in some ways been both of them. The scathing commentaries about HG had me in stitches: not because they were outright funny, but because I’d known my share of such people. One of the things that I really liked about Asach was, despite all the experience that this individual had, despite all that this person had seen, mistakes were still made based on preconceptions and assumptions. I really, really liked a very competent person could and would misunderstand despite the fact there was no deception, no hidden agendas. Laurel was not a bad character, but not as relatable for some reason. The hypercompetent are a bane of SF with unrealistic expectations of problem resolution. Its nice to see a more realistic take on the polymath than what I have in the past: Manfred Macx and Carlos Wu, I’m looking at you. Perhaps she was simply not given enough time on page for me to build up some understanding of her past her as an engine of the plot.

I did have an issue with the ending, a bit in certain regards, but it was not one that was out of place for the genre. Unfortunately, in a setting like this, I have an issue in some ways with the basic premise. In a current world of Digital Globe and Landsat and whatnot, I’m more than surprised that, well, anything would be left unfound on a world. We’re entering a world of cubesat sized spysats soon and given that the 2nd Empire of Man has at least 100 years on us…well…if you can accept that, then all else falls into place.

The book in general is good. The beginning a bit denser in the beginning, but once I was in, I was really in. The ending could use some shoring up, but I liked it. I’m intensely interested in a sequel. Whither New Utah under the Empire? Whither the Mote under the Empire? I sincerely hope Pournelle the Younger takes up the pen once more and should she, I’d be delighted to buy the book. I strongly recommend that you do, too. (ie: Go and buy it!)

Sunday, April 21, 2013

Avrora and I watched this live. NASA is getting 8 flights for $1.9 billion. About $238 million per flight. That means that the flights themselves will be cheaper for commercial customers. If the ratio that SpaceX has holds true, the flight cost will be around $105 million each. Not as good as SpaceX, but far, far better than ULA which starts at $250 million.

Friday, April 19, 2013

a. Professor of Veterinary Anatomy, School of Veterinary Medicine, Professor of Earth and Environmental Sciences, School of Arts and Sciences, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA 19104-6045, USA.

Abstract:

The taxonomic history of the Ceratopsia began in 1876 with the description of Monoclonius crassus Cope followed in 1889 by Triceratops horridus Marsh. After a peak of discovery and description in the 1910s and 1920s resulting from the Canadian dinosaur rush in the province of Alberta and the Central Asiatic Expeditions to Mongolia of the American Museum of Natural History, the study of ceratopsians declined to a low level until the 1990s, when discoveries in China, Montana, Utah, Alberta, and elsewhere, abetted by increased biostratigraphic and phylogenetic precision, led to an unprecedented resurgence of activity. Even Richard C. Fox, along with colleagues from Peking University, joined in the activity, by naming Psittacosaurus lujiatunensis. To place the activity in historical perspective, half of all known ceratopsians have been described since 2003. Despite important finds of basal ceratopsians in China, Mongolia, and Korea, North America continues to dominate ceratopsian, especially ceratopsid, diversity.

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

e. Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, Centre for Microscopy Characterisation and Analysis & Centre for Exploration Targeting, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia

Abstract:

Exceptional 3-D preservation of Ediacaran rangeomorph fossils is found on a single bedding plane at Spaniard's Bay, Newfoundland. This high-quality preservation has previously been explained by entrainment of organisms within the Td-e mudstone division of a distal turbidite, followed by encasement within concretions. Our sedimentological and taphonomic analysis reveals a clear association between these fossils and evidence for erosive unidirectional flows, including scours marks, tool marks, ridge-and-groove marks, parting lineations and current crescents. We suggest an alternative sequence of events that runs broadly as follows: (i) rangeomorph discs were anchored to the seafloor during deposition of planar laminated silts (our unit 2, less than 10 mm thick; Td), now bearing pyrite framboids and pyritized organic matter; (ii) rangeomorph fronds were then felled and entrained by high velocity unidirectional currents, to lie within their own erosional scours at the top of unit 2, or to form tool marks; (iii) this topography was then draped and cast by soft-weathering sand (unit 3, Tc) associated with the growth of early diagenetic pyrite around sand grains. Pyrite grains also appear to have replaced clumps of organic matter. Fossil impressions have since been exposed by differential weathering of the ferruginous sands with respect to the silts. This new context now provides a parsimonious explanation for a range of hitherto paradoxical structures. Features previously regarded as microbial mats (‘bubble trains’) that formed in the lee of sinuous ripples on the top of unit 2 may be explained as load-casts, or by localised gas escape within areas of lowered hydraulic pressure. Rangeomorph fronds remarkably preserved in positive (rather than the more usual negative) epirelief are explained by means of sediment-casting of branches that became ruptured in the high velocity current. Paradoxical structures previously thought to be enclosing biological ‘sheaths’ around rangeomorph fronds are reinterpreted as scour marks, whereas imbricate overlaps of first order branches in Beothukis, Trepassia and Avalofractus are explained by hydraulic shear, driven by overlying currents across ruptured and deflated fronds. We find that rangeomorph bodies could be deflated, imbricated, folded over, inverted, and infilled with fine sediment. Our hydraulic model provides a null hypothesis against which future observations of rangeomorph fronds can now be tested. It removes some significant anomalies in our understanding of rangeomorph architecture, and provides a better understanding of the physical properties of their body tissues, permitting the possibility of a reasoned consideration of their puzzling biological affinities.

Thursday, April 18, 2013

Diseased ancestor or mini-me? The debate over where the so-called "hobbit," or Homo floresiensis, came from has raged since researchers discovered its remains on the remote Indonesian island of Flores in 2003. Some researchers said its diminutive size was the result of disease, while others believed it descended from a small-bodied human ancestor.

But a new study, published April 17 in the journal Proceedings of the Royal Society B, says that clues to the hobbit-like human's ancestry lies in the size of its brain. The hobbit's gray matter is actually slightly larger than previously thought, according to the study's authors.

The so-called hobbit, which stood three feet (one meter) tall, lived on Flores until approximately 17,000 years ago. Previous studies examining H. floresiensis's skeleton ruled out the possibility of a disease called microcephaly as the cause of its small stature.

But if it was a new species of human, who was its ancestor?

Dwarfism?

One possibility is that the hobbit evolved from another small-bodied, small-brained early human, or "hominin," called H. habilis. The main problem with this theory is that there is no evidence that H. habilis ever made it to Southeast Asia, let alone Flores. (Explore the human evolutionary highway in this interactive.)

Other researchers have argued that H. floresiensis is descended from the larger-bodied H. erectus, widely considered to be the first hominin to leave Africa. Remains of H. erectus have been found throughout Asia, including on the Indonesian island of Java.

According to this hypothesis, H. erectus somehow made its way to Flores, where its descendants shrunk in size through a process called island dwarfism, in which species grow smaller to make the most of limited resources. (Related: "'Hobbits' Had Million-Year History on Island?")

"Some recent [animal] examples suggest that island dwarfism may be a fairly rapid process, [occurring] within a few thousand or even a few hundred years, but each case may be different," said study coauthor Yousuke Kaifu, a senior researcher at the National Museum of Nature and Science in Tokyo.

But critics of this theory have argued that the brain size difference between H. erectus and H. floresiensis—991 cubic centimeters (cc) and about 400 cc, respectively—represents an extreme and unprecedented example of island dwarfism. For comparison, modern humans have an average brain size of about 1,300 cc.

"Many recent researchers apparently suppose this is impossible," Kaifu said in an email.

Plausible Differences

But in their new study, Kaifu and his colleagues showed that the size gap is actually smaller than previously thought. Using a new high-resolution CT scanning technique, the team created a 3-D model of an 18,000-year-old H. floresiensis skull and calculated its brain volume to be about 426 cc.

In our solar system, only one planet is blessed with an ocean: Earth. Our home world is a rare, blue jewel compared to the deserts of Mercury, Venus and Mars. But what if our Sun had not one but two habitable ocean worlds?

Astronomers have found such a planetary system orbiting the star Kepler-62. This five-planet system has two worlds in the habitable zone -- the distance from their star at which they receive enough light and warmth for liquid water to theoretically exist on their surfaces. Modeling by researchers at the Harvard-Smithsonian Center for Astrophysics (CfA) suggests that both planets are water worlds, their surfaces completely covered by a global ocean with no land in sight.

"These planets are unlike anything in our solar system. They have endless oceans," said lead author Lisa Kaltenegger of the Max Planck Institute for Astronomy and the CfA. "There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy. Nonetheless, these worlds will still be beautiful blue planets circling an orange star -- and maybe life's inventiveness to get to a technology stage will surprise us."

Kepler-62 is a type K star slightly smaller and cooler than our Sun. The two water worlds, designated Kepler-62e and -62f, orbit the star every 122 and 267 days, respectively.

They were found by NASA's Kepler spacecraft, which detects planets that transit or cross the face of their host star. Measuring a transit tells astronomers the size of the planet relative to its star.

Kepler-62e is 60 percent larger than the Earth while Kepler-62f is about 40 percent larger, making both of them "super-Earths." They are too small for their masses to be measured, but astronomers expect them to be composed of rock and water, without a significant gaseous envelope.

As the warmer of the two worlds, Kepler-62e would have a bit more clouds than Earth according to computer models. More distant Kepler-62f would need the greenhouse effect from plenty of carbon dioxide to warm it enough to host an ocean. Otherwise, it might become an ice-covered snowball.

"Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions. Kepler-62f would be cooler, but still potentially life-friendly," said Harvard astronomer and co-author Dimitar Sasselov.

"The good news is -- the two would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future," he added.

The Paleoproterozoic Hekou Group in the western Yangtze Block is a volcano-sedimentary succession that is intruded by gabbroic plutons. Sedimentary rocks in the group include slates, marble and meta-siltstones interlayered with felsic metavolcanic rocks, metabasalts and metatuffs. Both the volcanic rocks of the Hekou Group and gabbros have undergone upper greenschist to lower amphibolite facies metamorphism. Metatuff samples from different layers have average zircon U-Pb ages of ~1697 Ma, slightly older than the intruding gabbroic plutons with zircon U-Pb ages of ~1684 Ma. Both metabasalts and metagabbros have similar elemental and isotopic compositions, indicative of a co-magmatic origin. They are rich in TiO2 (mostly greater than 2.5 wt.%), Zr (94.5–347 ppm), Ta (0.48–3.00 ppm) and Th (1.05–7.61 ppm) with high Nb/Y ratios (mostly great than 0.6) and LREE-enriched chondrite-normalized REE patterns, resembling within-plate mafic rocks. Their positive whole-rock εNd(t) (0.2 to +3.4) and zircon εHf(t) values (−3.3 to +8.4) suggest contributions from a depleted mantle source. The large range of εNd(t) and εHf(t) values, and variable degrees of Nb-Ta anomalies (Ta/LaPN = 0.17–1.75) are indicative of crust contamination during magma ascending. Both the metabasalts and metagabbros are considered to have formed in a continental rift setting.

Detrital zircon grains from meta-siltstones in the Hekou Group have U-Pb age populations mainly at 2070–1880 Ma, 2330–2250 Ma and 2900–2700 Ma. These age populations are comparable to those of the North Australian and North China Cratons in the Columbia supercontinent. However, in terms of geochemical features, the ~1.7 Ga within-plate mafic rocks at Hekou are similar to those from the ~1.7 Ga Leichhardt and Calvert Superbasins of the North Australian Craton, but different from those from the 1.7–1.2 Ga Zhaertai-Bayan Obo rift zone of the North China Craton. It is thus suggested that the Yangtze Block was more likely linked with the North Australian Craton in Columbia during the Late Paleoproterozoic. These rifting basins and mafic rocks may record the initial break-up of the Columbia supercontinent.

Though they be but little, they are fierce. The most powerful batteries on the planet are only a few millimeters in size, yet they pack such a punch that a driver could use a cellphone powered by these batteries to jump-start a dead car battery – and then recharge the phone in the blink of an eye.

Developed by researchers at the University of Illinois at Urbana-Champaign, the new microbatteries out-power even the best supercapacitors and could drive new applications in radio communications and compact electronics.

Led by William P. King, the Bliss Professor of mechanical science and engineering, the researchers published their results in the April 16 issue of Nature Communications.

“This is a whole new way to think about batteries,” King said. “A battery can deliver far more power than anybody ever thought. In recent decades, electronics have gotten small. The thinking parts of computers have gotten small. And the battery has lagged far behind. This is a microtechnology that could change all of that. Now the power source is as high-performance as the rest of it.”

With currently available power sources, users have had to choose between power and energy. For applications that need a lot of power, like broadcasting a radio signal over a long distance, capacitors can release energy very quickly but can only store a small amount. For applications that need a lot of energy, like playing a radio for a long time, fuel cells and batteries can hold a lot of energy but release it or recharge slowly.

“There’s a sacrifice,” said James Pikul, a graduate student and first author of the paper. “If you want high energy you can’t get high power; if you want high power it’s very difficult to get high energy. But for very interesting applications, especially modern applications, you really need both. That’s what our batteries are starting to do. We’re really pushing into an area in the energy storage design space that is not currently available with technologies today.”

The new microbatteries offer both power and energy, and by tweaking the structure a bit, the researchers can tune them over a wide range on the power-versus-energy scale.